Eosinophils are bone marrow-derived granulocytes implicated beneficially in host defense against infection, in anti-tumor cytotoxicity, and in wound healing. The abundance of eosinophils can contribute to inflammation, such as in the respiratory mucosal tissue from patients with asthma or rhinitis (see, e.g., Yuan et al., J. Exp. Med., 1997, 186:313-333).
Mast cells reside within the connective tissue of a variety of tissues and vascularized organs. They are also found at interfaces between the internal and external environments, such as the dermis, gut mucosa and submucosa, conjunctiva, pulmonary alveoli and airways, and the atrial appendage of the heart, where they can respond to foreign organisms and antigens. Inflammatory and allergic reactions involve mast-cell degranulation and mast-cell activation producing release of inflammatory factors and local or systemic immediate hypersensitivity reactions. Imbalance or improper regulation of mast cell activity is associated with detrimental exaggerated reactions to antigen observed in disorders such as anaphylaxis, atopy, and rhinitis.
There is a need for therapies to manage or treat eosinophil or mast cell related disorders effectively.